Flotation apparatus



June 2, 1931. J p, RUTH, JR 1,807,876

FLOTATI ON APPARATUS Filed Feb. 28, 1928 2 Sheets-Sheet l June 2, 1931. J. P. RUTH, JR

FLOTAT I ON APPARATUS Fiile d Feb. 28, 1928 2 Sheets-Sheet 2 Patented June 2, 1931 UNITED STATES PATENT OFFICE FLOTATION arrmrns Application filed February 28, 1928. Serial 1T0. 253,978.

This invention relates to improvements in flotation apparatus of the type shown and described in U. S. Letters Patent 1,277,750, granted September 3, 1918.

6 In the treatment of mineral ores it is customary to agitate the pulp in a chamber containing a liquid with which there is mixed a certain proportion of oil. This methodof separation is well known and is carried out in 10 different types of ap aratus, of which the one shown in the U. Letters Patent above identified, is one specific type. In the treatment of ores by means of flotation machines, it is necessary to pass the ore consecutively through a number of flotation cells arranged in series and then to pass the froth through another series of cells for the purpose of. cleaning after which the froth is passed through another cell for finishing. The froth is then subjected to a dewatering operation and the concentrate transferred to the smelter for final treatment. Where flotation cells are employed, it is customary to place the cells on a level floor and to transfer the froth 5 from one set of cells to another by means of centrifugal pumps. Froth of the type resulting from this process of separation is usually very diflicult to handle and therefore much power is consumed in raising-the froth from one level to the other in the manner now commonly done.

It is the object of this invention to assemble the different cells employed in carrying out the method of flotation separation in a series in which no two cells are placed on the same level but each adjacent cell is on a higher level than the one directly below so as to form an inclined series whose angular relation to the horizontal is such that a launder symmetrically arranged with respect to the difierent cells will have a downward inclination of sufficient an ularity to permit the froth to flow by the action of gravity alone. The separate units of the flotation series are each provided with an elevating means and are also so arranged that the tailings from one cell will flow by the action of gravity to the receivlng chamber of the next higher cell. The pulp is fed into one of the cells located a distance downwardly from the upper end of the series and the tailings will automatically passfrom one cell to the other and be discharged into the dump from the highest cell. The froth from the different cells in the roughing series flows into a common launder which carries it downwardly and deposits it in the receiving compartment of the lowermost cell of the cleaning series, where it is subjected to retreatment and from which it passes into a finishing cell after which it is dewatered and the concentrate subjected to the usual smelting operation.

11 order to more clearly describe my invention, it is necessary to have reference to. the accompanying drawings in which the invention has been illustrated and in which:

Fig. 1 is a side elevation with parts broken away and with parts of the cell omitted showing one series of my flotation apparatus;

, ig. 2 is a section taken on line 2-2, Fig. 1

Fig. 3 is a side elevation of two adjacent flotation cells with parts broken awayand parts shown in section to better disclose the construction Fig. 4 is a section taken on line 44, Fig. 3; and

Fig. 5 is a section taken on line 55, Fig. 4.

The cell employed and which forms the separate units of my apparatus has been shown in section in Fig. 4, from which it will so be seen that it has a bottom member 1 from the rear end of which the back side 2 extends upwardly and a front side 3 which extends upwardly to a much lesser extent than the side 2. A partition member 4 is located about half the distance between sides 2 and 3 and extends parallel with the latter. The ends of the machine are formed by end members 5 and 6. Partition 4 separates the machine into two compartments one of which has been designated by A and the other by B. Compartment A will be referred in as the receivmg compartment, while compartment B will be referred to as the separating or frothlng compartment. From the drawings it will be seen that the lower end of partition 4 terminates above the bottom of compartment A so as to form an opening 7 through which compartments A and B are in communication. Compartment A. is provided no to rotate the impeller.

with a bottom member 8 which is provided with a central opening 9. Extending upwardly from the sides of the machine are supporting timbers 10 to the upper ends of which I have secured a frame work comprising the channel-irons 11 and the channels 12 that are secured to the front ends of channel-irons 11. A motor 13 is secured to the rear flanges of channel-irons 12 by means of bolts 14. Secured to the front flanges of channel-irons 12 is a casting 15 on which is supported a bearing 16 in which the upper end of shaft 17 is rotatably supported. Secured to the sides 5 and 6 are channel-irons 18 and 19 that extend forwardly beyond the partition wall 4 and to the front ends of which the angle 20 is secured. A base 21 is secured to the vertical flange of angle 20 by means of bolts or rivets 22 and this base carries a bearing 23 through which shaft 17 extends. The lower end of shaft 17 has secured to it an impeller 24 which is located in the receiving chamber below the bottom member 8. Belts 25 serve to transmit power from the motor 15 to the impeller shaft, and A partition member 26 extends from the bottom of the separating chamber to the rear wall 2 at an angle of about forty-five degrees in the manner shown in Fig. 4. Located directly in front of the back wall 2 about half the distance between wall 2 and partition 4 is a plank 27 to the lower edge of which an inclined plank 28 is secured. Plank 28 lies in a plane substantially parallel to the inclined bottom member 6 and terminates a short distance to the rear of partition 4 so as to form an opening 29. Secured to the partition member 4 is a curved late 30 whose lower edge rests on a trianguar block 31. The space bounded by sides 5 and 6, wall 2 and plank 27 is divided into rectangular openings by means of spaced partitions 32 and 33 which cross each other at right angles. These partitions rest on supporting bars 34. Secured to the upper end of partition member 4 is a downwardly inclined plate 35 whose lower end 36 lies in a vertical plane. A wall 37 extends downwardly from the underside of plate 35 and is placed against the front side of partition member 4 in the manner shown in Fig. 4. This plate is secured to the partition member by screws or bolts, which, however, have not been shown. The upper end of partition 4 forms an overflow for the tailings. Located above late 35 is a spout having a bottom formed y plate 38 which extends parallel to 35 and is spaced therefrom so as to form a passageway 39 through which the tailings may flow into the conduit 40. Plate 38 has upwardly extending end walls 41 and has a portion 42 extending diagonally downward on the inside of partition 4 and this diagonal plate terminates in a vertical flange 43. The parts indicated by numerals 35 and 38 may be separate or may be formed from a single casting. Located directly beneath the lower end of plate 38, is a launder 44 which receives the froth that overflows into the chute formed by plate 38 and end walls 41. The level at which the froth overflows is determined by the height to which the wall is built up above the apex formed by parts 38 and 42. In order to make the froth overflowlevel adjustable, the sides of the machine has been provided with grooves 45 within which are located the ends of the steel bars 46. These bars are preferably about one-half inch thick and are placed one on top of the other to the height found most desirable.

The pulp is delivered into the receiving compartment A and will flow through the opening 9 into the compartment below the bottom member 8. The revolving impeller 24 will force the pulp through the opening 7 into the lower end of the separating compartment causing it to flow in the direction of arrow 47. As the capacity of the impeller is greater than the rate at which the pulp is fed into the receiving compartment, the latter will always be kept comparatively empty, with the result that air will be sucked downwardly through opening 9 and will mingle with the pulp so that the latter will be mixed with air bubbles such as indicated by numeral 48. The pulp that flows through opening 7 will pass between walls 26 and 28 and will follow the direction of arrow 49 upwardly through the openings between the rectangularly placed partitions 32 and 33. The air bubbles will pass upwardly above the liquid level indicated by line 50 and form the froth indicated by numeral 51. A portion of the tailings will follow the path indicated by arrow 52 and pass upwardly between the inner surface of partition 4 and the vertical flange 43 and thence through the opening 39 into conduit 40, and will flow by the action of gravity into the receiving compartment of the machine directly above. After the level of the froth has reached beyond the top of the wall formed by bars 46, the froth will overflow into the froth chute and will pass from thence into the launder 44, which must be inclined at such an angle that the froth will flow by the action of gravity alone.

Owing to the action of the impeller, the liquid level 50 can be maintained as high above the bottom of the reception chamber as may be desired, and in this way the overflow for the tailings can 'be at such a height that the can readily be transferred through the con uits 40 to the cell located adjacent but at a higher level, and in this way it is ossible to cause the tailings to flow upwardalong the series of cells and at the same time conduct the froth downwardly so as to deliver it to the lowermost cell of the next group in a manner which will be hereinafter more fully described. The difference in level between the adjacent cells and the difl'erence in level between the overflow of the tailings and the top of the receiving chamber, should be so proportioned that the tailings will flow by the action of gravity alone, not only to the cell located directly above, but to the second cell and in this manner make it possible to remove one cell for the purpose of repair, without thereby stopping the operation of the entire series. The inclination of the bottom of conduit 40 when one of the cells has been removed, has been indicated by dotted line 53 in Figs. 1 and 3.

I want to calfat'te'fition" to the fact that conduits 40 are slidable transversely of the cells or in the direction of the series. For the purpose of making them adjustable in this direction, a bar 54 has been provided across the top of each of the receiving compartments and the bottom of each conduit is provided with a bracket, 55, secured to the bottom near the upper end thereof. This bracket is provided at its l wer end with a fork 56 that straddles the ba; .54 and the lower end of the conduit is provided with a similar fork that straddles the bar 54 in the receiving compartment of the next higher cell. The upper edges of the side walls .of conduit 40 extend upwardly beyond the sides of the passage 39 in the manner shown in Fig. 4. When conduits 40 are moved towards the rights in the manner shown at the left hand machine in Fig. 3, a portion of the tailings will flow meral 58- designates the hopper throughwhich the pulp is fed to the receiving. chamber of the first cell in the groups where the roughing operation takes place. This group has been indicated by letter C and consists of eight cells placed in a row and each at a successively higher level. By the means described above, the tailings from each cell is transferred to the receiving compartment of the cell above, while the froth from all of the cells in group C is delivered to the common launder 44, and is carried. by the latter to the lowermost machine in the cleaning grou which has been represented by letter D. t a point directly above the receiving chamber of the lowermost cell in group D, the launder has been provided with a transverse partition-59, which serves to 'sto the downward flow of the froth and the wa l of the launder has been rovided with an opening 60 through whic into the receiving compartment of this cell.

the froth flows I this to the third cell in the manner above described. The tailings from the UPPBP'.

most cell of the cleaning series, will be delivered to the receiving compartment of the lowermost cell in group C and will pass through all the cells in the roughing group and will finally discharge through the chute 40 of the uppermost cell, from which it is transferred to the dump by suitable launders.

The froth from all of the cells in the cleaning group D is deposited into the upper compartment 61 of launder 49 and flows downwardly until it strikes the transverse partition 62 when it flows through the opening 63 into the receiving compartment of the finishing cell. The froth from this cell is delivered into the upper compartment 64 of the launder and flows from thence to a storage tank or is transferred to the smelter by any suitable means. The tailings from the finishing cell are transferred by conduit 40 to the receiving compartment of the lowermost cell in the cleaning series and are transferred by consecutive steps through all the 'cells and is finally discharged through the conduit 40 of the uppermost cell in group C.

From the above description it will be apparent that I have produced a flotation apparatus in which advantage is taken of the difference in the liquid level between the pulp in the receiving compartment and that in the separating compartment, caused by the action of the impeller, to transfer" the tailings from a lower to a higher level and thereby make it possible to transfer the froth by gravity from the roughing cells to the cleaning cells and from the cleaning cells to the finishing cell.

By the simple expedient of making conduit 40 slidable, I am able to recirculate a portion of the pulp in each machine and thereby produce more efi'ective separation with a smaller number of cells.

By means of the arrangement described,

it is also possible to introduce the tailings from the cleaning group into the receiving compartmentcf the lowermost cell of the roughing grou and in like manner to introduce the ta1 ings from the finishing cell into the receiving compartment of the lowermost cell in the cleaning group without mak mg it necessary to resort to the use of cen trifugal pumps, but to take advantage of the centrifugal action of the impeller with which each machineis provided.

By means of thearrangements of cells above described the installation of an apparatus for the carrying out of the flotation process is greatly simplified and 'cheapened. t is apparent that any capacity desired can be obtainedby using as many series of groups such as illustrated in Fig. 1 as may be desired.

The arrangement of cells in such a way that the tailings will pass from a machine at a lower level to a machine at a higher level through a series of cells, and at the same time the froth will flow by gravity downwardly to the lowermost cell of another series results in a great economy of construction and operation, which applicant therefore desires to claim broadly as his invention. i

The receiving compartment which is located above the bottom member 8 serves merely as an extension of the conduit 40 for the purpose of conducting the tailings to the opening 9 from which they pass into the agitating chamber below the bottom 8. In the claims therefore the word conduit will be used to designate compartment A as well as member 40.

Having described the invention what I claim as new is:

l. A flotation apparatus comprising a plurality of flotation machine cells arranged in groups, comprising several cells each, the cells of each group being located at different levels, the several groups being located at different levels, means for delivering the pulp to the lower cell of the higher group, means for transferring the tailings from each cell in a group to a higher cell, and means for delivering the froth from all of the cells of the upper group to the lowermost cell of the next lower group.

2. A flotation apparatus comprising, in combination, a plurality of cells, each of which has a pulp receiving conduit and a frothing compartment connected by a passage in which is located an impeller for transferring pulp to the froth compartment, said cells being arranged in a group, each cell of which is on a different level, each cell having an overflow for tailings and another overflow for froth, the level of the tailings overflow being higher than the top of the receiving conduit of the next higher cell, a condult located beneath the tailings overflow and extendin to the receiving compartment of the next higher cell, said conduit being inclined at such an angle that the tailings will flow by the action of gravity alone and movable transversely of the cell so as to receive all or a part only of the tailings and a froth launder located beneath the froth overflows of the several cells, said launder being inclined at such an angle that the froth will flow by the action of gravity alone.

3. A flotation apparatus comprising a group of flotation cell units for'roughing purposes arranged at different levels and each unit consisting of an agitating compartment for receiving the material to be treated and a separating compartment, the latter having a froth discharge and a gravity tailings discharge, the tailings discharge of any lower unit being in communication with the receiving compartment of the next higher unit of said group through a conduit inclined at such an angle that the tailings will flow by the action of gravity alone, a common launder to receive the froth discharge from all of the roughing units, a cleaning unit located below the lowermost unit of the roughing group and of substantially the same construction as the units of said group, the froth launder being downwardly inclined at such an angle that the froth will flow by the action of gravity alone and located in proximity to the various units and in comunication with the receiving compartment of the cleaning unit, the tailings discharge of the cleaning unit being higher than and in communication with the receiving compartment of the lowermost roughing unit, and a finishing unit located below the cleaning unit and substantially of the same construction as the other flotation units, the froth discharge of the cleaning unit being higher than and in communication with the agitating compartment of the finishing unit and the tailings discharge of the finishing unit being higher than and in communication with the receiving compartment of the cleaning unit.

4. A flotation apparatus comprising a group of flotation unitsfor roughingpurposes said units being arranged at different levels and each consisting of an agitating compartment for receiving the material to be treated and a frothing compartment in communication with the receiving compartment by a passageway, an impeller in the passageway for raising the level of the material in the frothing passage, the latter having a froth discharge and a tailings discharge, the tailings discharge of any lower unit being higher than and in communication with the receiving compartment of the next higher unit, a launder downwardly inclined in proximity to the units of the roughing group and arranged to receive the froth discharge from all of said units and to transfer it by the action of gravity alone, a cleaning group of units located below the lowermost unit of the roughing group, the several units of the cleaning group being at different levels, the tailings discharge of any lower unit of a cleaning group being higher than and in communication with the receiving compartment of the cleaning unit next above,

the receiving compartment of the lowermost.

cleaning unit being in communication with the froth launder of the roughing group, and a finishing unit located below the lowermost unit of the cleaning group and having its receiving compartment in communication with the froth discharge from the various units of the cleaning group.

5. A flotation cell having a frothing compartment and an agitatitn compartment, said frothing compartment having an overflow for tailings, a conduit located underneath the tailings overflow so as to receive the tailings, said conduit being movable transversely of the cell so that it may receive all or a part only of the tailings and means for conducting the tailings that are not received by the conduit in the agitating chamber.

6. A flotation apparatus having a plurality of cells each of which is located at a different level than its adjacent cell, each cell having a receiving conduit and a frothing compartment that are in communication with each other through an opening, means for transferring pulp from the receiving conduit to the frothing compartment and for maintaining the pulp level in the frothing compartment higher than the level in the receiving conduit, the frothing compartment having a pulp overflow and a forth overflow, the pulp overflow being located at a higher level than the receiving conduit of the next higher cell, means for conducting pulp from the pulp overflow of each cell to the receiving conduit of the next higher cell, a second group of cells of similar construction located below the first group with the upper cell of the second group below the lower cell of the first group and a common inclined launder passing underneath the froth overflows of the first group and extending to the receiving conduit of the lower cell of the second group, the pulp overflow of the upper cell of the second group being in communication with the receiving conduit of the lower cell of the first group.

7. A flotation apparatus having a plurality of cells each of which is located at a different level than its adjacent cell each cell having a receiving conduit and a frothing compare ment that are in communication with each other through an opening, means for transferring pulp from the receiving conduit to the frothing compartment and for maintaining the pulp level in the frothing compartment higher than the level in the receiving conduit, the frothing compartment having a pulp overflow and a froth overflow, the pulp overflow being located at a higher level than the receiving conduit of the next higher cell, means for conducting pulp from the pulp overflow of each cell to the receiving conduit of the next higher cell, a second group of cells of similar construction located below the first group with the upper cell of the second group below the lower cell of the first group, a common inclined launder passing underneath the froth overflows of the first group and extending to the receiving conduit of the lower cell of the second group, the pulp overflow of the upper cell of the second group being in communication with the receiving conduit of the lower cell of the first group and a third group of similar cells similarly arranged and located below the lowermost cell of the second group, the pulp overflow of the upper cell of the third group being in communication with the receiving conduit of the lower cell of the second group and a common launder passing underneath the froth overflows of the second group and extending to the receiving conduit of the lower cell of the lowest group.

8. A flotation apparatus composed of a plurality of substantially identical cells, each cell having a receiving conduit and a frothing compartment that are in communication with each other through an opening and means for transferring pulp from the receiving conduit to the frothing compartment and for maintaining the pulp level in the frothing compartment higher than the level of the pulp in the receiving conduit, the cells being arranged in a plurality of groups, all of the cells being arranged on an incline in which each cell is higher than any cells below it, the frothing compartment of each cell having a froth overflow and a pulp overflow, the pulp overflow of each cell below the upper one being above and in communication with the receiving conduit of the next higher cell, means for delivering pulp to the receiving conduit of the lower cell of the upper group a launder passing beneath all of the froth overflows of the cells of the upper group and extending to the receiving conduit of the lower cell of the next lower group and a similar launder passing beneath the froth overflows of the second group to the receiving conduit of the next lower group.

9. A flotation apparatus composed of a plurality of groups of flotation cells the groups and the separate cells being arranged on an incline, each cell having a. receiving conduit and a frothing compartment, each frothing compartment having a pulp and a froth overflow, means in each cell for transferring the pulp from the receiving compartment to the frothing compartment and for aerating the pulp, said means also maintaining the pulp level in the frothing compartment above the pulp level in the receiving compartment, means for delivering pulp from the frothing compartments of each cell below the highest cell in the series to the receiving conduit of the next higher cell, said means comprising a chute inclined from the pulp overflow of the lower cell to the receiving conduit of the higher cell, means for delivering pulp to the receiving conduit of the lowermost cell of the highest group, a common launder passing under the froth overflows of all the cells in each of the higher groups and extending to the receiving conduit of the lowermost cell of the next lower group and means for transferring pulp from the pulp overflow of the highest cells of the series to a dump.

In testimony whereof I afiix my signature.

JOSEPH P. RUTH, JR. 

